Centre drills
Start from the form, because it decides what kind of seat you cut. A centre drill opens the small conical seat that gives a drill a stable place to start, or that receives a lathe centre. It is short and rigid by design, because that rigidity is exactly what stops the next tool wandering off the mark.
THE FORM (DIN 333)3
The form is the first choice. DIN 333 standardises three centre-drill forms: R, A and B. All three cut a 60° seat, exactly matching a lathe centre; what differs is what surrounds it. The matching seat in the workpiece is standardised by DIN 332-1.
The size is written as the pilot diameter: A 2.0 means form A with a Ø2 mm pilot. On each product page you pick the pilot diameter (D1) and the shank (D2).
How deep? Go in until roughly half to two thirds of the 60° shoulder is engaged. That is enough bearing surface for the centre to seat; any deeper and you are opening up the part for nothing and loading the thin pilot, which is the most fragile part of the tool.
The standard form: a 60° pilot and a 60° countersink, with no protective outer angle. The default for most work, where the part is set up once and the centre is not at risk of being knocked afterwards. The simplest and most economical choice.
The same as A, plus an outer 120° chamfer. The 120° recesses the 60° cone below the surface and shields it from chips and knocks when you take the part out and re-mount it. The right choice for precision shafts that pass through several setups.
A radius instead of a straight cone. The curve reduces the contact area with the lathe centre and leaves room for oil inside the seat, while also giving better holding accuracy and less stress concentration. The form for grinding and high-precision shafts.
THE MATERIAL YOU ARE CUTTING4
Start here. Pick the material you are cutting and the collection filters down to only the tools that work it. The letters P/M/K/N/S/H are the ISO 513 standard, used by every manufacturer; the same letter means the same material in any catalogue.
In detail, per group: [P] Steel · [M] Stainless · [K] Cast iron · [N] Aluminium.
Plain and alloy steels: the largest and most forgiving group. They give a long, continuous chip, so chip control is what matters.
Stainless steels. They work-harden locally as you cut them, weld to the edge, and do not carry heat away. They want cobalt, a steady feed with no dwelling, and plenty of coolant.
Cast irons. They give a short, crumbling chip, but the material is abrasive and eats the cutting edge. Here you need abrasion resistance, not heat resistance.
Non-ferrous: aluminium, brass, copper. Soft and fast, but they throw a bulky chip that sticks. They want few flutes, large flute valleys and high revs.
THE TOOL MATERIAL3
Click a material to filter the collection. For a detailed description of the grades see the Cutting Tool Materials article.
The classic high speed steel with high hardness and resistance to fracture, ideal for straightforward work.
High speed steel with 5% cobalt for increased resistance to high temperatures. Suitable for stainless (INOX) and hard steels.
Tungsten carbide with cobalt, extremely hard and rigid. For very high cutting speeds in CNC and maximum tool life, but sensitive to vibration and impact.
THE COATINGS1
The coating you will find on our centre drills. Click to see only those.